Artificial Reefs on the way for Moreton Bay

THE rec fishos of south-east Queensland, who have been waiting nearly three years for compensation after losing access to 17 per cent of Moreton Bay to marine park rezoning, finally have cause to celebrate.

THIS week, Fisho's marine biology editor Dr Ben Diggles visited a construction site where the first purpose built artificial reef structures destined for installation in Moreton Bay are being manufactured.

The company responsible is Korean-based Haejoo Ltd, internationally recognised as experts in artificial reef design and construction.

Ryan Paik, executive director of Haejoo's Australian branch, explained how each type of module has been specifically designed to maximise fish production.

"We care about fish, so it's important that the designs provide not only structure to attract bigger fish, but sufficient shelter and internal void volume to allow fish larvae to settle and recruit as juveniles to the reefs.

"The durable steel and concrete construction materials are environmentally friendly and at the same time maximise surface area for settlement of fouling organisms", Paik said.

Ryan Paik, executive director of Haejoo's Australian branch, is
an artificial reef expert with a wealth of knowledge on reef design and
construction.

The concrete fish boxes measure 4x4x4 metres, weigh 17 tonnes each, and are designed to form fish habitat in water around 25 metres deep. The fish boxes will be deployed in 4 arrays of 5 boxes located at the top of Moreton Island. In addition, three of the 11 metre high, 11 metre wide, 15 tonne, all steel "fish cave" reefs will be deployed in water around 35-40m deep east of Bribie Island.

This is the first time purpose built deepwater artificial reefs have been deployed in Australia. Exciting stuff for fishos in Moreton Bay, who have waited nearly three years for compensation after losing access to 17 per cent of the bay to marine park rezoning in 2008.

The concrete structures have a minimum life expectancy of 40 years, the steel ones 30 years, and it seems they comfortably exceed that design specification, with some of the company's first reefs (deployed in Korea around 45 years ago) still operational today.

A 4m high , 17 tonne "fish box", fresh out of the mould.
These reinforced concrete structures are specifically designed to
provide fish habitat in water around 25m deep.

An open day will be held for the general public, this Sunday 10th April 2011 at 405 Thynne road, Morningside from 10am till 1pm, so interested fishos can inspect the structures. Ryan from Haejoo has a wealth of knowledge on artificial reef
development, and will be present at the open day to answer questions about the project. This will be the last chance to see them up close before the steel fish caves are deployed first, hopefully on schedule in the first suitable weather window after the 18th of April.

It should take only a few months before the reefs begin to fish well, with their benefits becoming greater as time goes by.

The first stage of manufacture of a concrete fish box involves placement of the
reinforcing inside the mould.

With the unprecedented rollout of marine parks threatening fishing access throughout the country, let's hope that more government decision makers see the environmental benefits of artificial reefs as a way of compensating fishers and enhancing fisheries productivity in areas which otherwise could become significantly degraded by displaced fishing pressure being concentrated into a smaller areas.